Once you've chosen your dream house, it's time to put your offer in to the estate agent or direct to the seller, depending who you are buying from. Your offer should be based on sound judgement, on what the property is worth - not on your desire to secure the property at any cost.
You will need to take into account factors such as; the condition of the property, how long it has been on the market, and whether or not there the price has been dropped. Good research at this point will always pay off.